Yeah, pre-COIE would be good. More streamlined and the characters had less accumulated baggage. It would redeem a lot of them who've been pretty tainted by a lot of problematic stuff (Bruce wouldn't be an abusive asshole, Barry wouldn't have the "dead mom", Wally wouldn't have had to go through HiC, etc.).
Yeah there's a lot of good stuff that came after, but most of that has been ruined anyway and the actual comics are still available. I don't think defaulting back to pre-COIE would rule out later characters being worked back in either.